The present invention relates to the field of data communications. More particularly, the present invention relates to a method and system to abort information being transmitted over a communications network.
Communication networks have become virtually indispensable in building a thriving economy and typically play an essential role in generating prosperity in a modem society. Communication networks permit users to readily gain access to and exchange information of all types (e.g., sound, text, numerical data, video, graphics, multimedia, etc.). Increasing communication efficiency facilitates greater productivity and reduced costs in numerous activities. Information transmitted over communication networks is utilized in the performance of a number of functions, including the conveyance and analysis of ideas and trends in most areas of business, science, education and entertainment. Typically, a communications network transmits a significant amount of information to peripheral devices for processing and use in performing designated tasks.
The amount of information flowing through a typical communication network is not constant. At times the peripheral devices coupled to a communication network require more information to perform their designated tasks than other times. In addition, most communication systems are expanded over time to include additional peripheral devices, resulting in increased demands for bandwidth. Bandwidth is the amount of data transmitted over a communications network in a given period of time. Even if the absolute number of peripheral devices coupled to a communication network does not change, older peripheral devices are usually replaced by newer, more advanced peripheral devices that increase bandwidth requirements.
Generally, communication network resources are relatively expensive and it is uneconomical to build a network with enough bandwidth to instantaneously handle all possible information transmission requests under worst case scenarios. Communication networks built with the ability to handle the maximum possible communication load that all the peripheral devices could generate if they all tried to access the network at one time are usually inefficient. In such a communication network some network resources are usually idle most of the time and typical communication networks are built with limited resources. Upgrading communication network facilities to provide increased bandwidth capacity for new peripheral devices is usually an expensive, time-consuming, and disruptive process. Communication network facility upgrades are not undertaken lightly and advanced communication networks are typically harder to maintain, service, and administer.
Even though limiting communication network resources is economically efficient in many instances, the limitation impedes a system""s performance in certain situations. Complicating matters is the fact that communication networks do experience higher activity and traffic at certain peak operating times. For example, a communication network""s resources are usually pushed to capacity when numerous multiple peripheral devices attempt to log onto and transmit data over the network simultaneously or when an application is transmitting a very large file in a burst. In such situations some of the peripheral devices can not communicate with one another and a transfer of information is delayed. When the amount of data to be transmitted exceeds a network""s bandwidth, the network becomes overloaded and the time or xe2x80x9clatencyxe2x80x9d for transmitting a packet of data increases dramatically.
Usually, communication systems convey a wide variety of information and some information is more critical than other information to the operation of peripheral devices. A number of factors contribute to the importance or priority of a particular piece of information or data. In many instances, operational constraints of peripheral devices dictate that certain information is essential to the operations of a system and has more sensitive latency tolerances. It is also important to retain adequate bandwidth resources to transmit network control commands and information related to maintaining an adequate flow of information through a communication network. For example, key network administration data, such as communication network control information, is typically critical to the operation of the communication network.
Communication of information is usually restrained during times of peak communication traffic, including delays in communication of high priority information. Since most communication networks experience some periods of increased communication traffic, limited bandwidth generally leads to important or high priority information not being conveyed in a timely manner. Typically such communication networks are administered in a manner that permits only one device or entity to communicate on a path at a time and devices typically have to compete for communication network resources. Usually the basic operating principle of such a system is the items first in are those first out (FIFO). The resulting xe2x80x9cqueuingxe2x80x9d of information presents additional problems. As long as lower priority information, such as information related to non-critical activities (e.g., e-mail messages, etc.) is being transmitted on a communications network, successive higher priority information cannot be transmitted over the network.
A number of communication networks operate in an environment in which information is divided into segments or frames. Typically, one segment of information is transmitted at any given time and other frames wait in turn until the opportunity arises for them to be sent over the network. Data that is not sent is dropped or the device it originated from has to keep attempting to get it onto the network. Delays incurred while a device waits to obtain access to network resources increases the detrimental affects of queuing high priority traffic behind lower priority traffic. In addition to waiting for lower priority data to complete transmission, once high priority data reaches the top of the queue it must wait while network resources become available. Data comprising important information should be transmitted expeditiously in order to keep the communication network and components or devices coupled to it operating properly.
Peripheral devices typically require a certain minimal bandwidth or amount of critical information to be conveyed in a timely manner to maintain adequate operational performance. The more efficiently a communication network utilizes its limited resources the greater the probability it will be capable of addressing network control and peripheral component requirements. The efficiency of a communication system is determined by a number of factors. For example, a communication system""s maximized utilization of its entire throughput or bandwidth capabilities greatly enhances the amount of information that is transmitted over a communication network in a specific period of time. An efficient communications network also has the ability to expeditiously transmit high priority data.
What is required is a system and method that provides access to communication network resources in an efficient and timely manner. The system and method should permit information transmissions to be aborted and facilitate the availability of communication network resources for other communications. The system and method should increase the probability that higher priority data in fixed length data communication frames is granted access to communication bandwidth expeditiously while minimizing impacts to communication flow and conserving communication network resources. For example, it should be applicable to existing communication networks in a manner that preserves the usefulness of communication protocols while minimizing adverse affects on network infrastructure.
The present invention is a system and method that provides access to communication network resources in an efficient and timely manner. The system and method of the present invention permits information transmissions to be aborted and facilitates the availability of communication network resources for other communications. The system and method increases the probability that higher priority data in data communication frames are granted access to communication bandwidth expeditiously while minimizing impacts to communication flow and conserving communication network resources. For example, it is applicable to existing communication networks in a manner that preserves the usefulness of communication protocols while minimizing adverse affects on network infrastructure.
In one embodiment of the present invention, standard error detection indicators are manipulated to cause information in aborted communication frames transmissions to be discarded. For example, a cyclical redundancy check (CRC) is utilized in one embodiment of the present invention. When a frame is intentionally aborted during transmission an non-matching CRC is inserted, such as a one""s compliment of the correct CRC. The present invention is implemented in a number of communications network systems and methods, such as a wireless communication system that transmits a media access control (MAC) frame with a data unit payload. In another embodiment, the present invention operates in a data cable system that transmits a data over cable media access control (MAC) frame with an Ethemet/[ISO8802-3] type packet protocol data unit payload. In one embodiment of the present invention, communication frames are aborted in order to make communication resources available for transmission of higher priority data.